Tube press with mandrel adjustment

ABSTRACT

Some tube presses need a device for adjusting both the longitudinal position and the angular position of the mandrel. The longitudinal position of the mandrel is adjusted by rotating a nut on a spindle connected to the mandrel. Previously such devices have included separate coupling members for preventing rotation of the spindle with respect to the nut and rotation of the spindle with respect to the press. I now provide a single coupling member which is rotationally fixed with respect to the spindle and which can move between two positions, in one of which the spindle is rotationally fixed with respect to the nut and in the other of which the spindle is rotationally fixed with respect to the press.

United States Patent [451 Mar. 28, 1972 Groos [54] TUBE PRESS WITHMANDREL ADJUSTMENT [72] Inventor: Horst Hans Groos, Metzkausen, Germany[73] Assignee: Schloemann Aktiengesellschaft, Dusseldorf, Germany [22]Filed: Dec-10,1969

21 Appl.No.: 883,901

[52] U.S.Cl ..72/265, 72/273 [51] lnt.Cl. B2lc23/20,B21c 25/00 [58]FieldotSearch.... ..72/265,264, 273

[56] References Cited UNITED STATES PATENTS 3,277,692 10/1966 Gettig..72/265 X 3,123,215 3/1964 Zilges ..72/265 Linnerz PrimaryExaminer-Charles W. Lanham Assistant Examiner-R. M. RogersAttorney-Holman & Stern [5 7] ABSTRACT Some tube presses need a devicefor adjusting both the longitudinal position and the angular position ofthe mandrel. The longitudinal position of the mandrel is adjusted byrotating a nut on a spindle connected to the mandrel. Previously suchdevices have included separate coupling members for preventing rotationof the spindle with respect to the nut and rotation of the spindle withrespect to the press. 1 now provide a single coupling member which isrotationally fixed with respect to the spindle and which can movebetween two positions, in one of which the spindle is rotationally fixedwith respect to the nut and in the other of which the spindle isrotationally fixed with respect to the press.

6 Claims, 4 Drawing Figures PATENTEDMAR28 m2 SHEET 1 OF 2 WT vRA/EY:

PATENTEDmma x972 SHEET 2 OF 2 INVENTOR. HORST HANS GROOS.

BY )vwmM A D/ firrmuevs TUBE PRESS WITH MANDREL ADJUSTMENT The inventionrelates to a press for forming tubes (usually metal tubes), the presshaving a device for adjusting the iongitudinal position of the mandrelto which a rotatable nut is screwed on to a screw-threaded spindleconnected to the mandrel holder, the nut being carried by a carryingmember (for instance a mandrel crosshead) which is movable in alongitudinal direction with respect to the press; the spindle can berotated and can be locked either with respect to the nut or with respectto the carrying member.

It is thus possible to adjust the longitudinal position of the mandreland to adjust the angular position of the mandrel. The latter adjustmentis necessary when nonround tubes are being extruded and the mandrel hasto be centered relative to the shaped die, while the adjustment of thelongitudinal position of the mandrel is necessary to make it possible touse mandrels of different lengths. Mandrels of different lengths may beused either because the mandrels become worn or because of the diameterof mandrel required, those of smaller diameter generally being shorterfor reasons of strength.

In one arrangement for adjusting the longitudinal position and angularposition of the mandrel, there are two independent coupling members, oneof which is connected to the nut and the other of which is connected toan extension on the end of the press ram piston, the connections beingeither rotatable or fixed. This mandrel adjusting system is howevercostly and is also difficult to operate and can be unreliable inoperation since it is possible to fix both securing memberssimultaneously; in the latter circumstances, if a drive motor isactuated to rotate the nut (for instance using a worm drive), themandrel adjusting system would be seriously damaged. Another, lessharmful possibility of incorrect operation, which nonetheless must bepossible at any time in practice, is that both securing members maysimultaneously be rotatable or only halftightened so that when the drivemotor is actuated, the desired adjustment would not occur. In addition,when the press rarn piston is used to carry one of the securing members,construction costs are increased by having to secure the ram pistonagainst rotation.

According to the present invention, there is provided a press forforming tubes, the press having a mandrel holder,

a screw-threaded spindle connected to the mandrel holder,

a rotatable nut for adjusting the position of the spindle and of themandrel holder in a longitudinal direction,

a carrying member (for instance a mandrel crosshead) carrying the nut,the. carrying member being movable in a longitudinal direction withrespect to the press,

means for rotating the spindle and moving the spindle longitudinally,normally by rotating the nut,

a coupling member movable in a longitudinal direction with respect tothe spindle and to the nut but rotationally fixed with respect to thespindle, and

means for moving the coupling member in a longitudinal direction betweenone position in which the coupling member couples with the nut andanother position in which the coupling member couples with the carryingmember.

The invention can simplify the design and operation of the mandreladjustment system and increase the reliability of the press inoperation.

Said positions of the coupling member are preferably end positions ofits longitudinal movement with respect to the nut. In order to providemating connections between the coupling member and the nut or carryingmember, the coupling member may have teeth or dogs on each of oppositeend portions, and the nut and the carrying member may have correspondingteeth or dogs, so that in said one position the teeth or dogs on the nutengage with the teeth or dogs on one end portion of the coupling memberand in said other position, the teeth or dogs on the carrying memberengage with the teeth or dogs on the other end portion of the couplingmember. That is to say that when one set of teeth or dogs disengages,the other set engages.

In order to obtain a rapid and simple axial movement of the couplingmember, at least two rods may be connected to the coupling member, therods being longitudinally slidable and rotatable about the axis of thespindle with respect to the carrying member, the rods being secured to alongitudinally movable control member (preferably a plate) forcontrolling the position of the coupling member.

The adjustment device of the invention may be used in tube presseshaving a piercing mandrel either behind or in front of the presscylinder. In the latter case, in particular, the coupling member mayhave a sleeve which engages in a bore in the spindle and is rotationallyfixed with respect to the spindle, in order to reduce the length of thecarrying member and hence of the press as a whole.

In general, the coupling member is preferably rotationally fixed withrespect to the spindle by having at least one longitudinal groove in thespindle in which engages a projecting member on the coupling member. Inthe specific case of the coupling member having a sleeve, referred toabove, a coupling member having such a projecting member engaging in agroove in a bore in the spindle has the advantage over a coupling memberwith a projecting member engaging in a groove in the screw-threading inthe spindle in that the length of the spindle required is substantiallyshorter because the paths of movement of the projecting member and ofthe screw-threading are located at the same position along the spindle,whereas in the latter case, the paths of movement must be displaced fromeach other because the nut and the projecting member cannot besuperimposed.

The invention will be further described, by way of example, withreference to the accompanying drawing, in which:

FIG. 1 is a vertical section through a ram crosshead and adjacent partsof a press in accordance with the invention, taken along the line of I-Iof FIG. 2;

FIG. 2 is a section along the line IIII of FIG. 1;

FIG. 3 is a section along the line III-lll of FIG. 2; and

FIG. 4 illustrates part of FIG. 1, on a larger scale.

A hollow ram piston 2 is able to slide longitudinally in a cylinder 1and act upon a crosshead 3. The front of the latter (left-hand side inFIG. 1) is a hollow press ram 4 which may be pushed into a container(not shown) having a die. The crosshead 3 contains a hollow cylinder 5,the rear end of which projects into the hollow ram piston 2.

A piston 6 slides in the hollow cylinder 5 and is able to push themandrel crosshead, which is composed of parts 7,8,9, towards the leftrelative to the ram crosshead 3. The crosshead 3 is provided on eitherside with an opening 10, out of which arms 38 of the mandrel crosshead7,8,9, extend. The ram crosshead 3 slides on inclined sliding surfaces13 as indicated in FIG. 3, while the mandrel crosshead is able to slidein a longitudinal direction on the lower part of the ram crosshead 3 bymeans of guide strips 14. A mandrel holder 15 is able to slidelongitudinally in the crosshead 7,8,9. The right-hand end of the mandrelholder 15 is provided with a mandrel supporting spindle 16 with externalthreading 17. On its left-hand end the mandrel holder 15 carries,conventionally, a mandrel 18. The effective length of the mandrel isvariable because it is desirable that the press functions satisfactorilywith mandrels 18 of different lengths. This is why the mandrel holder 15is made longitudinally slidable relatively to the mandrel crosshead7,8,9.

The spindle 16 is enclosed by a nut 19 which is rigidly connected to asleeve 20. This sleeve 20 carries a worm wheel 21 which is driven by aworm 22 arranged in the part 8 of the mandrel crosshead 7,8,9 (FIG. 4).The worm 22 may be driven by an electric motor (not shown in thedrawing). The nut 19 is itself rotatably mounted in and carried by themandrel crosshead 7,8,9 (which thus acts as a carrying member for thenut), the mandrel crosshead 7,8,9 both carrying the nut by way ofbearing surfaces engaging the nut directly and carrying the nut by wayof the spindle 16.

The sleeve 20 is provided at its end with coupling dogs 23 with whichcoupling dogs 24 of a changeover coupling 25 can mesh. The coupling 25also has dogs 26 in which engage apropriately shaped dogs 27 on a fixedsleeve 28, when the coupling 25 is, as shown in FIG. 4, pushed towardsthe right. The sleeve 28 is fixed in a central bore in the mandrelcrosshead part 9, and, although the sleeve 28 moves longitudinally withthe mandrel crosshead 7,8,9 the sleeve 28 cannot rotate. A long couplingsleeve 29 of the coupling 25 projects into the spindle 16 and carries aspline or key 30 which excludes the possibility of the spindle 16 andsleeve 29 rotating relatively to each other but does permit the twoparts to effect a relative longitudinal movement.

The changeover coupling 25 may be pushed in an axial direction by two ormore rods 31 connected to a control disc 32. If this disc is pushed inthe direction of the arrow 33 (FIG. 4), the changeover coupling 25 alsomoves towards the left, the coupling between the dogs 26 and 27 isbroken and a coupling effected between the dogs 23 and 24.

Pistons 35 are rigidly secured to an intermediate wall 36 of the ramcrosshead 3 and project into hydraulic cylinders 37, which are rigidlymounted in the arms 38 of the part 7 of the mandrel crosshead 7,8,9.When the cylinders contain pressurized fluid, they thrust the mandrelcrosshead 7,8,9 within the ram crosshead 3 towards the right, i.e.,backwards. The arms 38 further have two apertures 39, through whichthere project rods 40. The right-hand end of each rod 40 is fixed, beingrigidly secured to the press cylinder 1.

Each rod 40 carries at its left-hand end a bayonet member 41 and acorresponding hollow bayonet member 42 is inserted in each aperture 39.The two hollow bayonet members 42 each carry a lever 43, as is shownonly in FIG. 3. The lever 43 forms an angle of 225 with the vertical.The ends of both levers 43 are articulated to a control rod 44. If thelatter is pushed towards the left in the direction of the arrow 45, thetwo hollow bayonet members 42 are turned through 45 and in this positionno longer allow passage to the bayonet member 41 so that the bayonetmember 41 forms a stop for the arms 38 of the mandrel crosshead 7,8,9,when this latter is advanced towards the left.

Pistons 47 are also rigidly connected to the arms 11 and 12 of the ramcrosshead and extend towards the rear, i.e., to the right, where theyproject into the press return cylinder 48. Finally, the arms 11 and 12each have a hole 49, through which is passed the respective rod 40. Theholes 49 serve as abutments for the rods 40.

If a billet is to be pierced, the piercing piston 6 of the cylinder isactuated by pressurized fluid so that the mandrel crosshead 7,8,9 ismoved towards the left, causing the-mandrel 18 to project out of thepress ram 4 and travel through the container into the die, so that thebillet is pierced. After the billet has been pierced, the tube can beextruded by introducing a higher pressure into the press cylinder 1. Themandrel crosshead 7,8,9 does not now travel towards the left but abutswith its arms 38 or hollow bayonet members 42 on the bayonet members 41.

As a result of this abutment, the mandrel 18 is held fast during theextrusion process, assuming, of course, that the valves in the piercingcylinder 6 are open. After the extrusion process, the ram crosshead 3 isretracted. If it is desired to use a shorter mandrel 18 than that shown,the point of the mandrel must take up the same position relative to thedie as did the previous mandrel. To ensure that it does so, the mandrelholder is moved to the left relatively to the mandrel crosshead 7,8,9,for a distance equal to the amount by which the new mandrel is shorterthan the mandrel 18 shown in the drawing. This is effected by turningthe nut 19, thus causing the spindle 16 of the mandrel holder 15 to bepushed towards the left because it is prevented from rotating by the keyor spline 30. The next working cycle may then take place in the manneralready described.

It is, of course, necessary for the mandrel 18 to be able to rotateabout its longitudinal axis if tubes with a cross-sectional shape otherthan circular are to be extruded. This conventional rotation of themandrel 18 about its longitudinal axis is made ossible by pushin thechangeover coupling 25 towards the le t as shown in F1 4. The changeovercoupling 25 is then freed from the dogs 27 on the fixed sleeve 28 sothat when. the worm 22 rotates with the nut 19, the spindle 16 of themandrel holder 15 also rotates. The worm 22 thus now serves to rotatethe mandrel l8.

1 claim:

1. A press for forming tubes, the press having a mandrel holder,

a screw-threaded spindle connected to the mandrel holder,

a rotatable nut for adjusting the position of the spindle and ofthemandrel holder in a longitudinal direction,

a carrying member carrying the nut, the carrying member being movable ina longitudinal direction with respect to the press,

means for rotating the spindle and moving the spindle longitudinally,

a coupling member movable in a longitudinal direction with respect tothe spindle and to the nut but rotationally fixed with respect to thespindle, and

means for moving the coupling member in a longitudinal direction betweenone position in which the coupling member couples with the nut, therebypermitting rotation of the spindle, and another position in which thecoupling member couples with the carrying member, thereby permittinglongitudinal movement of the spindle.

2. A press as claimed in claim 1, wherein said positions of the couplingmember are end portions of its longitudinal movement with respect to thenut.

3. A press as claimed in claim 1, wherein the coupling member has teethor dogs on each of opposite end portions, and the nut and the carryingmember have corresponding teeth or dogs, whereby in said one positionthe teeth or dogs on the nut engage with the teeth or dogs on one endportion of the coupling member and in said other position the teeth ordogs on the carrying member engage with the teeth or dogs on the otherend portion of the coupling member.

4. A press as claimed in claim 1, wherein at least two rods areconnected to the coupling member, the rods being longitudinally slidableand rotatable about the axis of the spindle with respect to the carryingmember, the rods being secured to a longitudinally movable controlmember for controlling the position of the coupling member.

5. A press as claimed in claim 1, wherein the coupling member has asleeve which engages in a bore in the spindle and is rotationally fixedwith respect to the spindle.

6. A press as claimed in claim 1, wherein the spindle has at least onelongitudinal groove and the coupling member has a projecting memberengaging in the groove.

1. A press for forming tubes, the press having a mandrel holder, ascrew-threaded spindle connected to the mandrel holder, a rotatable nutfor adjusting the position of the spindle and of the mandrel holder in alongitudinal direction, a carrying member carrying the nut, the carryingmember being movable in a longitudinal direction with respect to thepress, means for rotating the spindle and moving the spindlelongitudinally, a coupling member movable in a longitudinal directionwith respect to the spindle and to the nut but rotationally fixed withrespect to the spindle, and means for moving the coupling member in alongitudinal direction between one position in which the coupling membercouples with the nut, thereby permitting rotation of the spindle, andanother position in which the coupling member couples with the carryingmember, thereby permitting longitudinal movement of the spindle.
 2. Apress as claimed in claim 1, wherein said positions of the couplingmember are end portions of its longitudinal movement with respect to thenut.
 3. A press as claimed in claim 1, wherein the coupling member hasteeth or dogs on each of opposite end portions, and the nut and thecarrying member have corresponding teeth or dogs, whereby in said oneposition the teeth or dogs on the nut engage with the teeth or dogs onone end portion of the coupling member and in said other position theteeth or dogs on the carrying member engage with the teeth or dogs onthe other end portion of the coupling member.
 4. A press as claimed inclaim 1, wherein at least two rods are connected to the coupling member,the rods being longitudinally slidable and rotatable about the axis ofthe spindle with respect to the carrying member, the rods being securedto a longitudinally movable control member for controlling the posiTionof the coupling member.
 5. A press as claimed in claim 1, wherein thecoupling member has a sleeve which engages in a bore in the spindle andis rotationally fixed with respect to the spindle.
 6. A press as claimedin claim 1, wherein the spindle has at least one longitudinal groove andthe coupling member has a projecting member engaging in the groove.